Salps (unidentified species)

A large salp drifted by the camera near to the cable at the base of Axial. Salps are planktonic tunicates, which belong to Phylum Chordata, along with all vertebrate organisms. Photo credit: NSF-OOI/UW/CSSF; V13.

Salps are planktonic tunicates, and are in Phylum Chordata along with fish and all vertebrate animals! They move by pumping water through their bodies, filtering phytoplankton for food as they pump. Salps have multiple life cycle stages that coexist in the open water. There are two general forms made by salps. One form is a small solitary gelatinous tube, and the other is long chain of individual tubes. Both forms can reproduce, and when food is plentiful salp populations can rapidly increase.

Salps are a common sight throughout the water column, especially at Slope Base and the base of Axial Seamount. There are several gelatinous and colonial chain salps at Axial, however, only one species has been captured in focus on the HD camera.

References:
http://oceana.org/en/explore/marine-wildlife/salp
http://science.kqed.org/quest/2012/07/03/ocean-overrun-with-gentle-gelatinous-salps/